Polyurethane-based plastics material (A), consists of an OH gp.-supplying polyol (I), an NCO gp.-supplying polyisocyanate (II), a chemically inert component (III), and opt. further standard additive. As (I), (A) contains (A) end-hydroxylated polybutadiene having average mol.wt. 2800, equiv. wt. 1200 and viscosity 500 mPa.sec. at 30 degrees C, (b) a polyether-polyester polyol having equiv.wt. 350 and viscosity 2500 mPa.sec at 25 degrees C, (c) 2-octyl-dodecanol as internal plasticiser and (d) standard polymerisation accelerators. (II) is diphenylmethane-4,41-diisocyanate and (III) is dipbenzyltoluene. Proportion of available (III) is 5-8 pts.wt. w.r.t. 100 pts.wt. (I)+(III). Wt. ratio (I):(III) is 1:1.75-1:2. (A) is used as filler material for hermetically sealing cable connections. A cable sleeve, contg. or consisting of hardened, mechanically stable plastics (B) filled with (A), to form an intimate adhesive bond between (B) material and (A), is claimed as part of a cable connection for signalling equipment consisting of bundled conductive core leads in a protective sheath, bonded terminally to other cables, and housed in a cable sleeve. (A) has good self-hardening properties and low viscosity for working at - 10 to +50 degrees C, high elasticity, residual adhesive power and adhesion, high moisture-impermeability, low notch resistance whereby embrittlement allows easy removal by hand on opening cable connections, and high electrical resistance, e.g. 1013-1014 OMEGA. cm. at 1 kv./mm.
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